Oil and gas drilling operations have evolved over the years to include multiple automated tool subsystems. Automated tool subsystems aid in executing repetitive tasks on the drill floor including drilling, tripping, casing, and cementing. Tool automation optimizes the rate of penetration, makes hole quality more consistent, reduces operation time, improves overall drilling performance, and reduces the cost of drilling operations. More importantly, tool automation reduces the number of people required to work in and around the hazardous drill floor environment. The overwhelming majority of drilling operations are not fully automated, therefore some tasks are still performed by humans working alongside heavy drilling machinery. The automated tool subsystems pose new challenges for maintaining a safe operating environment where man and machine must share the same workspace.
Collision avoidance is a component of automated tool subsystems that mitigates the possibility of two or more of these tools colliding with each other. The systems that attempt to mitigate tool collision are known by various names: anti-collision systems (ACS), collision avoidance systems (CAS), zone management systems (ZMS), but all share a common goal. In some tool collision avoidance applications, virtual and real world (Cartesian) coordinate systems are correlated and define the drill floor space. A bounding box surrounds a tool in virtual space and establishes a volume occupied by the tool. The bounding box may also be axis-aligned, in which case the virtual space surrounding the tool changes dynamically as the tool appendages extend, rotate, retract, raise, lower, etc. A proximity zone surrounds the bounding box and defines a hazardous area around the tool. Collision avoidance systems monitor tool positions and movement, and predict a location of a moving tool. Collision avoidance systems will override automated tool operations to prevent a virtual overlap of the projected bounding boxes, i.e. a real-world tool collision.
Despite the move towards automated tool subsystems, drill hands continue to be a necessary component of the drilling operation. Drill floor personnel are a dynamic component of the drilling operation that are not monitored by existing tool collision avoidance systems. Collision avoidance between drill floor personnel and automated tools depends on the situational awareness of the rig hands (i.e., drill floor personnel). The avoidance of an automated tool presents an unnecessary distraction to a drill hand in an already hazardous environment.